This invention relates to an improvement in a clutch type change speed apparatus used in a working vehicle such as an agricultural vehicle or tractor.
A known clutch type change speed apparatus of this type comprises four sets of constant mesh gear mechanisms provided for free rotation between a first transmission shaft and a second transmission shaft and having different reduction ratios, and hydraulically operable clutches between free rotation gears of the gear mechanisms and the transmission shafts supporting the free rotation gears, respectively. The clutches are selectively operable to provide four speeds through the gear mechanisms. (See Japanese Patent Application No. 59-186060, for example.)
Since in the above example simply the four gear mechanisms having different reduction ratios are provided between the first transmission shaft and the second transmission shaft to obtain the four speeds, the construction requires the four gear mechanisms which means the number of parts is correspondingly large and a large part of space in a transmission case is occupied by the gear mechanisms.